The present invention relates to a spooling device for sewing machines.
In spooling devices of conventional construction, the thread bobbin to be wound with thread can be placed on a winder shaft, and the winder shaft can be driven by the drive motor of the sewing mechanism for the sewing machine. Thus, arrangements are known wherein the spooling device is disposed on the shaft of the drive motor, with clutch means being provided for selectively coupling the motor shaft to the sewing mechanism or to the spooling device. The disadvantages in this construction reside in the fact that the spooling device is not in the field of vision of the operator; the feeding of the thread during spooling requires additional thread guide means; the winder shaft must be electrically insulated from the motor shaft; and the simultaneous steps of sewing and spooling is impossible.
Spooling devices have also become known, for example according to Swiss Patent No. 567,602 wherein the winder shaft is arranged in the region of the handwheel, drivable by the arm shaft of the sewing machine. The winder shaft can be placed in driving engagement with the handwheel by means of a displaceable friction wheel. Although this type of structure provides considerable advantages as compared with the first-mentioned arrangement, it is still deficient inasmuch as it requires, by necessity, the arrangement of the spooling device in the zone of the handwheel. Also, the friction-wheel drive is noisy in most cases and, on account of the unavoidable friction wheel abrasion, leads to an undesired contamination of the sewing machine.
In contrast to the above, the present invention has the purpose of providing a spooling device that can be located and/or operated locally and independently of the drive elements of the sewing mechanism, and can function without complicated or greatly wear-prone coupling means.
To achieve this object, the spooling device of the present invention is characterized in that its winder shaft is seated on the output shaft of a low-voltage motor associated with a switch, said switch being operated by means of a switching element responsive to the winding process.
The low-voltage motor, independent of the drive motor of the sewing mechanism includes, a winder shaft seated directly on its output shaft and serving for receiving the thread bobbin, makes it possible to arrange the spooling device practically at any suitable location of the sewing machine so that it can be optimally operated, provides a maximally simple thread feed, and can be activated while the sewing mechanism is in operation as well as while the sewing mechanism is at a standstill.
Suitably, the low-voltage motor with the winder shaft, the trigger element, and the switch is disposed on a support permitting various mounting possibilities at the machine housing, so that the preassembled spooling device can be mounted as a module in various positions, for example with a winder shaft that projects upwardly toward the handwheel side or forwardly out of the machine housing. An arrangement at the head of the machine can also be advantageous so that direct thread feed is possible from the needle to the bobbin on the winder shaft.
In case of electronic sewing machines, the arrangement of the spooling device directly beside the feed dog of the machine would also be possible. The spooling device could, in this case, be located underneath the same cover plate which is merely somewhat wider. The thread guided through the needle underneath the needle plate could then be directly guided to the bobbin and wound up.
The switching element is suitably a three-armed lever, pivotable in an axial plane through the winder shaft, the first arm being constructed for scanning the wound-up thread package, the second arm for operating the switch, and the third arm, in cooperation with an incline, for triggering the switchover step. Suitably, the feeler arm, which projects as is usual into the region of the bobbin out of the machine housing, serves simultaenously as a manually operable switch-on element.